Power related or mechanical devices, such as large electrical transformers, load tap changers, turbine gearboxes, circuit breakers, hydraulic fluid reservoirs, mechanical devices and/or gearboxes which require a dry blanket to, among other reasons, prevent moisture contamination of lubricant, and the like, typically include components immersed in oil, which is utilized to insulate, lubricate, cool and/or the like the components associated with the power related or mechanical devices. Because the oil expands and contracts with temperature changes, such power related or mechanical devices are provided with a head space above the oil that is vented to the atmosphere to control the pressure within, for example, an oil tank.
More specifically, as the tank increases in temperature, the oil in the tank expands, the pressure in the tank increases, and a portion of the air in the headspace is forced from the tank. When the tank begins to cool, the oil in the tank contracts, the pressure in the tank decreases, and air is drawn into the tank to equalize the pressure in the tank.
A dehydrator breather is conventionally utilized to regulate and condition the air flowing into and out of the tank. In some dehydrating breathers, a vent is provided between the tank and the outside air. A valve is positioned between the vent and the dehydrator breather that by opening and closing, as necessary, controls air flow into and out of the tank.
Often, the dehydrator includes a desiccant material, such as a silica gel, to remove any moisture from the air before it is allowed into the tank. Moisture entering the tank can be detrimental and has the capability of destroying the properties of the oil, damaging parts of the power related or mechanical device, or the like. Problems arise, however, when the desiccant is near capacity, at capacity, or is no longer able to absorb moisture. To address this issue, prior art devices have included a heater associated with the desiccant to encourage drying of the desiccant. This results in formation of condensation on the walls of the dehydrator breather. When the condensation returns to a liquid state, it flows out of the dehydrator via at least one drain. However, in order to operate the heater, the dehydrator has to be disconnected from the tank by operation of the previously mentioned valve, operated when the tank air is flowing out of the tank, and/or operated when air is not flowing at all. This can be difficult to determine, requires a complex control circuitry to operate, and still typically results in non-continuous and less than optimal operation.
Accordingly, it would be desirable to provide a dehydrator breather that can operate substantially continuously even during regeneration.